This invention relates to the field of systems for compiling images, more particularly systems that compile an image by merging additional images into an image buffer containing additional image information.
The advent of cost effective electronic computers has dramatically changed the printing industry. While just a few years ago printers relied on set type and photographic images, modem printers utilize streams of electronic information to describe the images to be formed. These streams of information typically convey information at a very high level in order to allow compatibility among a large range of printers. Modern page description languages are examples of the high level at which data is exchanged between the computer defining the image to be created and the printer creating the image.
While high level data is exchanged between the printer and the attached computer, this data must eventually be converted to some type of pixelated format or bitmap. A bitmap is a memory array that represents each location, or pixel, of the image or document to be printed. Each storage location in the bitmap corresponds to a specific portion of the image to be created. The data stored at the bitmap location, which may be a single bit or a digital word, determines the intensity and color of the image at that location. Multicolor images, or continuous tone images several bits to represent each pixel and are sometimes stored as a multiple arrays where each array is a separate bit-plane. A bit-plane consists of equally weighted bits from the entire bitmap.
Converting these image streams into an image bitmap requires each object described by the page description language to be merged into the image bitmap. This repetitive merging process, while relatively simple, consumes a very large amount of processing throughputxe2x80x94especially at the speeds consumers has come to demand. Although modern data processors have made great advances in throughput, the processing hardware drives up the cost of the printers. Efficient software, however, often lowers the recurring production costs by minimizing the processing power and memory included in the design. Therefore, there is a need in the industry for methods and systems that speed this merging process.
Objects and advantages will be obvious, and will in part appear hereinafter and will be accomplished by the present invention which provides a method and system for efficiently rendering a buffer. According to one embodiment of the claimed invention, a method is provided to render the buffer. The method comprises providing a band buffer stored in a first memory, providing an object mask, aligning the object mask with a predetermined tile grid, subdividing the object mask into tiles, locating active tiles in the object mask, transferring a portion of the band buffer corresponding to the active tiles into a second memory, modifying the portion of the band buffer based on a portion of the object mask corresponding with the portion of the band buffer, and returning the modified portion of the band buffer to the first memory.